Effect of freeze storage on the volatiles of butter

The changes in the volatile components of three butter samples were studied during freeze storage for 7.5 months. The amount of carbonyl increased and reached a maximum after 4.5 months of storage. Afterwards the carbonyl decreased. The lactons reached its maximum after storage of 3 month. The increase of the carbonyls caused by peroxidation of unsaturated fatty acids was taken as indication for the deterioration of the butter samples during storage.